Setting up a firewall

Just as a building or vehicle uses specially constructed walls to prevent
the spread of fire, so
computer systems use firewalls to prevent or limit access to
certain applications or systems and to protect systems from malicious attacks.

To create a firewall under QNX Neutrino, you can use a combination of:

IP Filtering to control access to your machine

Network Address Translation (NAT)—known to Linux users as
IP masquerading—to connect several computers through a common external interface